This invention relates generally to electronic devices and more particularly to communication cables for the transmission of digital data.
As the electronic age have progressed, electronic devices has reached into areas which were initially not contemplated. No longer is there a central computer room in which all of the sundry devices are housed within easy reach of each other. Today, electronics are truly ubiquitous with devices being found in homes, schools, factories, stadiums, and gyms. Indeed, it is difficult to identify a place where computers and their electronic cousins are not found.
As this proliferation has continued, there has been a growing need to permit these various devices to communicate with each other so that the assemblage is made more powerful.
The accepted maximum distances for transmission using an RS232 connector is about fifty feet; for TTL digital signals, the distance drops to only five feet.
For short distances of less than about one hundred feet, in-line amplification of a digital signal from a host computer has been sufficient to transmit the digital electronic signal along an interconnecting cable. This approach though assumes that the other end, the remote site, has its own power supply to also amplify the signal for the return trip.
Also, in some moderate distances, there are severe line-loss considerations which is addressed only by putting in intermediate stations which act to re-transmit the digital signals. This solution to the distance limitation increases the costs of the systems dramatically and also requires intermediate power sources between the two sites.
For extremely long distances, the use of the telephone lines and a Modem has been developed. The Modem modulates and demodulates signals so that the digital signals from a computer can communicate over established phone lines.
This solution is for extremely long distances and is not practical, due either to cost or complexity of installation, for shorter distances or where the location of the remote site is moved often.
It is clear from the foregoing that there is a need for a communication system which easily and inexpensively addresses the middle distances of over one hundred fifty feet but less than miles.